STEMax_PF: accurate and fast peak-finding for atom quantitative analysis

Aberration-Corrected Scanning Transmission Electron Microscopy (AC-STEM) offers sub-ångström resolution and has become the most microscopic and advanced tool in the field of materials science, yet its quantitative image analysis has been constrained by high computational demands, uneven background illumination, and challenges in resolving overlapping point spread functions. In this work, we introduce STEMax_PF, a novel software tool that integrates and improves multiple advanced techniques - including an adaptive threshold-enhanced centroid method, rapid normalized cross-correlation for detecting light atoms, and an improved weighted overdetermined regression algorithm - to effectively address these issues. In the two-dimensional Gaussian fitting process, STEMax_PF adopts a unique strategy by individually estimating the initial fitting parameters for each atomic column using several approaches, ensuring accurate fitting for materials comprising any elements. The integration of these methods dramatically reduces computational resource usage and enables extremely fast processing. Furthermore, STEMax_PF is universally applicable to any crystal structure and STEM image format, paving the way for reliable quantitative atomic analysis and its connection to phenomena such as ferroelectric polarization, piezoelectric/dielectric responses, and electron-phonon interactions.